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Abstract
INTRODUCTION This research evaluates the utility and precision of point-of-care ultrasound (POCUS) in urology, inspired by recent affirmations of its feasibility and value.1,2 Our study provides valuable insights for urologists about POCUS's practical usage. METHODS A prospective study assessed POCUS usage and accuracy in the University of Alberta's Division of Urology using data from April 4, 2022, to April 4, 2023. Data include POCUS indications, findings, and correlation with the final diagnosis/gold standard. Additionally, a qualitative survey was conducted among urologists and residents about POCUS's pros, cons, and barriers to integration. RESULTS Thirty-three patients underwent POCUS examinations, mainly for suspected hydronephrosis (27%, n=9). Other indications included urinary retention, testicular mass, torsion, cryptorchidism, renal mass, extended focused assessment with sonography in trauma (eFAST ) exams, nephrostomy tube placement confirmation, and scrotal hematomas. POCUS findings matched the final diagnosis in most cases, showing 86% sensitivity, with an average exam time of 1-5 minutes. POCUS showed potential for suprapubic tube insertions. Residents (60%, n=20) were the most frequent users, followed by staff (33%, n=10), and students (6%, n=2). The surveyed urologists and residents expressed comfort with POCUS but cited time, cost, and practicality as barriers. CONCLUSIONS POCUS proves accurate and beneficial in urology, particularly for hydronephrosis. Most findings align with the gold standard, and the average exam time is brief. Barriers include time and cost. Further research is necessary to evaluate cost-effectiveness and POCUS's impact on patient outcomes in routine urologic practice.
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Affiliation(s)
| | - Peter Metcalfe
- Division of Pediatric Surgery, Department of Surgery, University of Alberta, Stollery Children’s Hospital, Edmonton, AB, Canada
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2
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Nigam R, Field M, Harris G, Barton M, Carolan M, Metcalfe P, Holloway L. Automated detection, delineation and quantification of whole-body bone metastasis using FDG-PET/CT images. Phys Eng Sci Med 2023; 46:851-863. [PMID: 37126152 DOI: 10.1007/s13246-023-01258-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Accepted: 04/11/2023] [Indexed: 05/02/2023]
Abstract
Non-small cell lung cancer (NSCLC) patients with the metastatic spread of disease to the bone have high morbidity and mortality. Stereotactic ablative body radiotherapy increases the progression free survival and overall survival of these patients with oligometastases. FDG-PET/CT, a functional imaging technique combining positron emission tomography (PET) with 18 F-fluorodeoxyglucose (FDG) and computer tomography (CT) provides improved staging and identification of treatment response. It is also associated with reduction in size of the radiotherapy tumour volume delineation compared with CT based contouring in radiotherapy, thus allowing for dose escalation to the target volume with lower doses to the surrounding organs at risk. FDG-PET/CT is increasingly being used for the clinical management of NSCLC patients undergoing radiotherapy and has shown high sensitivity and specificity for the detection of bone metastases in these patients. Here, we present a software tool for detection, delineation and quantification of bone metastases using FDG-PET/CT images. The tool extracts standardised uptake values (SUV) from FDG-PET images for auto-segmentation of bone lesions and calculates volume of each lesion and associated mean and maximum SUV. The tool also allows automatic statistical validation of the auto-segmented bone lesions against the manual contours of a radiation oncologist. A retrospective review of FDG-PET/CT scans of more than 30 candidate NSCLC patients was performed and nine patients with one or more metastatic bone lesions were selected for the present study. The SUV threshold prediction model was designed by splitting the cohort of patients into a subset of 'development' and 'validation' cohorts. The development cohort yielded an optimum SUV threshold of 3.0 for automatic detection of bone metastases using FDG-PET/CT images. The validity of the derived optimum SUV threshold on the validation cohort demonstrated that auto-segmented and manually contoured bone lesions showed strong concordance for volume of bone lesion (r = 0.993) and number of detected lesions (r = 0.996). The tool has various applications in radiotherapy, including but not limited to studies determining optimum SUV threshold for accurate and standardised delineation of bone lesions and in scientific studies utilising large patient populations for instance for investigation of the number of metastatic lesions that can be treated safety with an ablative dose of radiotherapy without exceeding the normal tissue toxicity.
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Affiliation(s)
- R Nigam
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia.
- Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia.
- Illawarra Cancer Care Centre, Wollongong Hospital, Wollongong, NSW, 2500, Australia.
| | - M Field
- Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia
- Liverpool and Macarthur Cancer Therapy Centre, Liverpool, NSW, 2170, Australia
- South Western Sydney Clinical Campus, School of Clinical Medicine, University of New South Wales, Sydney, NSW, Australia
| | - G Harris
- Chris O'Brien Lifehouse, Camperdown, NSW, 2050, Australia
| | - M Barton
- Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia
- Liverpool and Macarthur Cancer Therapy Centre, Liverpool, NSW, 2170, Australia
- South Western Sydney Clinical Campus, School of Clinical Medicine, University of New South Wales, Sydney, NSW, Australia
| | - M Carolan
- Illawarra Cancer Care Centre, Wollongong Hospital, Wollongong, NSW, 2500, Australia
| | - P Metcalfe
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia
- Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia
| | - L Holloway
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia
- Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia
- Liverpool and Macarthur Cancer Therapy Centre, Liverpool, NSW, 2170, Australia
- South Western Sydney Clinical Campus, School of Clinical Medicine, University of New South Wales, Sydney, NSW, Australia
- Institute of Medical Physics, University of Sydney, Camperdown, NSW, 2505, Australia
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Lavoie C, Chapman DW, Bain A, Metcalfe P, Sarlieve P, Kiddoo D. Long-Term outcomes of cecostomy tube insertion for patients with bowel dysfunction: A retrospective review. J Pediatr Urol 2023:S1477-5131(23)00131-6. [PMID: 37130762 DOI: 10.1016/j.jpurol.2023.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 03/31/2023] [Accepted: 04/04/2023] [Indexed: 05/04/2023]
Abstract
BACKGROUND Constipation is common in the pediatric population and in severe forms it can lead to debilitating fecal incontinence which has a significant impact on quality of life. Cecostomy tube insertion is a procedural option for cases refractory to medical management, however there is limited data investigating the long-term success and complication rate. METHODS A retrospective review was performed evaluating patients at our centre undergoing cecostomy tube (CT) insertion between 2002 and 2018. The primary outcomes of the study were the rate of fecal continence at 1-year, and the incidence of unplanned exchanges prior to annual scheduled exchange. Secondary outcomes include the frequency of anaesthetic requirements and length of hospital stay. Descriptive statistics, t-test, and chi-square analysis was performed where appropriate using SPSS v25. RESULTS Of 41 patients, the average age at the time of initial insertion was 9.9 years with the average length of stay in hospital being 3.47 days. The most common etiology of bowel dysfunction was spina bifida, which was present in 48.8% (n = 20) of patients. Fecal continence was achieved in 90% (n = 37) of patients at 1 year and the average rate of cecostomy tube exchange was 1.3/year with an average of 3.6 general anaesthetics being required by patients and the average age of no longer requiring one being 14.9 years. DISCUSSION Analysis of patients undergoing cecostomy tube insertion at our centre has further supported the use of cecostomy tubes as a safe and effective option for management of fecal incontinence refractory to medical management. However, a number of limitations exist in this study including its retrospective design and failure to investigate changes in quality of life using validated questionnaires. Additionally, while our research provides greater insight to practitioners and patients what degree of care and types of complications or issues they may encounter with an indwelling tube over the long-term, our single-cohort design limits any conclusions that could be made regarding optimal management strategies for overflow fecal incontinence through direct comparison with other management strategies. CONCLUSIONS CT insertion is a safe and effective method for managing fecal incontinence due to constipation in the pediatric population, however, unplanned exchange of tube due to malfunction, mechanical breakage, or dislodgment occurs frequently and may impact quality of life and independence. LEVEL OF EVIDENCE IV.
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Affiliation(s)
- Callum Lavoie
- Division of Urology, Department of Surgery, University of Alberta.
| | - David W Chapman
- Division of Urology, Department of Surgery, University of Alberta
| | - Alex Bain
- Division of Urology, Department of Surgery, University of Alberta
| | - Peter Metcalfe
- Division of Urology, Department of Surgery, University of Alberta
| | - Philippe Sarlieve
- Department of Radiology and Diagnostic Imaging, University of Alberta
| | - Darcie Kiddoo
- Division of Urology, Department of Surgery, University of Alberta
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Patterson E, Stokes P, Cutajar D, Rosenfeld A, Baines J, Metcalfe P, Powers M. High-resolution entry and exit surface dosimetry in a 1.5 T MR-linac. Phys Eng Sci Med 2023; 46:787-800. [PMID: 36988905 DOI: 10.1007/s13246-023-01251-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 03/21/2023] [Indexed: 03/30/2023]
Abstract
The magnetic field of a transverse MR-linac alters electron trajectories as the photon beam transits through materials, causing lower doses at flat entry surfaces and increased doses at flat beam-exiting surfaces. This study investigated the response of a MOSFET detector, known as the MOSkin™, for high-resolution surface and near-surface percentage depth dose measurements on an Elekta Unity. Simulations with Geant4 and the Monaco treatment planning system (TPS), and EBT-3 film measurements, were also performed for comparison. Measured MOSkin™ entry surface doses, relative to Dmax, were (9.9 ± 0.2)%, (10.1 ± 0.3)%, (11.3 ± 0.6)%, (12.9 ± 1.0)%, and (13.4 ± 1.0)% for 1 × 1 cm2, 3 × 3 cm2, 5 × 5 cm2, 10 × 10 cm2, and 22 × 22 cm2 fields, respectively. For the investigated fields, the maximum percent differences of Geant4, TPS, and film doses extrapolated and interpolated to a depth suitable for skin dose assessment at the beam entry, relative to MOSkin™ measurements at an equivalent depth were 1.0%, 2.8%, and 14.3%, respectively, and at a WED of 199.67 mm at the beam exit, 3.2%, 3.7% and 5.7%, respectively. The largest measured increase in exit dose, due to the electron return effect, was 15.4% for the 10 × 10 cm2 field size using the MOSkin™ and 17.9% for the 22 × 22 cm2 field size, using Geant4 calculations. The results presented in the study validate the suitability of the MOSkin™ detector for transverse MR-linac surface dosimetry.
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Affiliation(s)
- E Patterson
- Centre of Medical and Radiation Physics, University of Wollongong, Wollongong, NSW, Australia.
| | - P Stokes
- Townsville Cancer Centre, Townsville Hospital and Health Service, Townsville, QLD, Australia
| | - D Cutajar
- Centre of Medical and Radiation Physics, University of Wollongong, Wollongong, NSW, Australia
| | - A Rosenfeld
- Centre of Medical and Radiation Physics, University of Wollongong, Wollongong, NSW, Australia
- Illawarra Health Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
| | - J Baines
- Townsville Cancer Centre, Townsville Hospital and Health Service, Townsville, QLD, Australia
- College of Science and Engineering, James Cook University, Townsville, QLD, Australia
| | - P Metcalfe
- Centre of Medical and Radiation Physics, University of Wollongong, Wollongong, NSW, Australia
- Illawarra Health Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
- Ingham Institute for Applied Medical Research, Liverpool, NSW, Australia
| | - M Powers
- Townsville Cancer Centre, Townsville Hospital and Health Service, Townsville, QLD, Australia
- College of Science and Engineering, James Cook University, Townsville, QLD, Australia
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Bouhadana D, de Lima S, Nguyen DD, Bhojani N, Lee JY, Metcalfe P, MacLellan DL, Domes T. Introducing the Canadian Urology Student Interest Group (CUSIG): Initial experience from a national webinar with recently matched Canadian urology residents for medical students. Can Urol Assoc J 2023; 17:137-141. [PMID: 36758179 PMCID: PMC10073528 DOI: 10.5489/cuaj.8206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- David Bouhadana
- Faculty of Medicine and Health Sciences, McGill University, Montreal, QC, Canada
| | | | | | - Naeem Bhojani
- Division of Urology, Université de Montréal, Montreal, QC, Canada
| | - Jason Y Lee
- Division of Urology, University of Toronto, Toronto, ON, Canada
| | - Peter Metcalfe
- Division of Urology, University of Alberta, Edmonton, AB, Canada
| | - Dawn L MacLellan
- Department of Urology, Dalhousie University, Halifax, NS, Canada
| | - Trustin Domes
- Division of Urology, University of Saskatchewan, Saskatoon, SK, Canada
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Sawchuk T, Metcalfe P. Teste Talk: A trial social media campaign to improve awareness of testicular torsion. Can Urol Assoc J 2023; 17:E110-E115. [PMID: 36758185 PMCID: PMC10132373 DOI: 10.5489/cuaj.8135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
INTRODUCTION Adolescent males are particularly prone to testicular torsion, often resulting in subsequent orchiectomy. A lack of knowledge about testicular pathologies, as well as hesitancy to discuss genital concerns, are fundamental, preventable barriers to early presentation. We hypothesized that a social media campaign to improve awareness of testicular torsion and other urological conditions affecting adolescents may overcome such barriers in this population. METHODS A social media campaign, "Teste Talk," was created and promoted on Instagram and Facebook. Data was collected from June 1 to December 1, 2021. Instagram followers, Facebook page likes, Instagram and Facebook reach, post likes, Instagram follower demographics, and advertisement data were reviewed. Data was collected using Meta Business Suite. Paid promotions to improve awareness of the campaign were targeted towards 13-18-year-old males in Alberta and were funded by the Undergraduate Research Initiative Support Fund. RESULTS The campaign reached 26 072 Instagram accounts and 14 741 Facebook accounts. The Instagram page amassed 382 followers, while the Facebook page accumulated 99 likes. Paid advertisements were seen 81 136 times on Instagram and Facebook. Instagram surveys demonstrated that over the study period, followers had an increased awareness of testicular torsion and how to recognize it. No patients presenting with torsion during the study period admitted to seeing the campaign. CONCLUSIONS Testicular torsion remains a significant issue among adolescent males, and creative ways to disseminate information and increase knowledge and conversations about testicular pathologies are needed. Social media campaigns present a potential pathway for increasing awareness and reducing delays to presentation and orchiectomies.
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Affiliation(s)
- Taylor Sawchuk
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Peter Metcalfe
- Department of Surgery, University of Alberta, Edmonton, AB, Canada
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Chan E, Martin P, Brighi C, Pillay S, Holloway L, Metcalfe P, Koh ES. NIMG-75. REPEATABILITY OF MANUAL SEGMENTATION OF GLIOBLASTOMA ON MRI - QUALITY ASSURANCE FOR A QUANTITATIVE MRI RADIOMICS REPEATABILITY STUDY. Neuro Oncol 2022. [DOI: 10.1093/neuonc/noac209.693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Abstract
BACKGROUND
Accurate and repeatable imaging segmentation of glioblastomas is important for effective radiomics modelling of clinical endpoints such as survival and treatment response. Manual and even automated segmentation are prone to variability. The primary objective of this study is to evaluate the repeatability of manually segmented glioblastomas on MRI which will serve as quality assurance for a quantitative MRI radiomics repeatability study.
METHODS
MRI datasets from n=19 patients with recurrent glioblastoma extracted from The Cancer Imaging Archive (RIDER Neuro MRI dataset) comprised of test-retest scans (time-point 1 and 2) acquired on average 2 days apart. The MRI protocol consisted of dynamic contrast-enhanced 3D FLASH using 0.1mmol/kg Magnevist intravenous injection at 3cc/second (TR 3.8ms, TE 1.8ms, 5mm slices, flip angle 25°), contrast-enhanced 3D FLASH (TR 8.6ms, TE 4.1ms, 1mm slices, flip angle 20°) and contrast-enhanced 3D FLAIR (TR 6000ms, TE 353ms, TI 2200ms, 1mm slices, flip angle 180°) on a 1.5T magnet. Contrast enhancing tumour from n=38 MRI scans were manually segmented by a radiologist slice by slice using contrast-enhanced 3D FLASH T1-weighted images on MIM software (v6.9.5). All cases at time-point 1 were contoured before contouring commenced for time-point 2 in the same order. Repeatability and spatial overlap was assessed by Dice similarity coefficient (DSC), Hausdorff distance (HD) and centroid shift.
RESULTS
A comparison of time-point 1 and 2 demonstrated the median DSC for n=19 cases was 0.84 (interquartile range 0.07), mean HD was only 0.1cm and mean centroid shift was 0.2cm.
CONCLUSION
High repeatability and spatial overlap of manually segmented contrast enhancing regions of recurrent glioblastoma were achieved on serial MRI. This substantiates a high level of repeatability which forms a core component of an MRI radiomics platform under development.
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Affiliation(s)
- Edward Chan
- Department of Radiology, Liverpool Hospital , Sydney, New South Wales , Australia
| | - Philip Martin
- Ingham Institute for Applied Medical Research & University of Wollongong , Wollongong, New South Wales , Australia
| | - Caterina Brighi
- ACRF Image X Institute, Sydney School of Health Sciences, The University of Sydney & Ingham Institute for Applied Medical Research, Sydney , Australia
| | - Sugendran Pillay
- Department of Radiology, Liverpool and Campbelltown Hospitals , Sydney, New South Wales , Australia
| | - Lois Holloway
- Ingham Institute for Applied Medical Research & Liverpool and Macarthur Cancer Therapy Centres, Sydney, Australia & South West Sydney Clinical Campus, University of New South Wales, Sydney , Australia
| | - Peter Metcalfe
- Ingham Institute for Applied Medical Research & Centre for Medical and Radiation Physics, University of Wollongong , Sydney, New South Wales , Australia
| | - Eng-Siew Koh
- Liverpool Hospital & South Western Sydney Clinical Campus, University of New South Wales , Sydney, New South Wales , Australia
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Martin P, Holloway L, Metcalfe P, Koh ES, Brighi C. Challenges in Glioblastoma Radiomics and the Path to Clinical Implementation. Cancers (Basel) 2022; 14:3897. [PMID: 36010891 PMCID: PMC9406186 DOI: 10.3390/cancers14163897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 08/04/2022] [Accepted: 08/09/2022] [Indexed: 11/17/2022] Open
Abstract
Radiomics is a field of medical imaging analysis that focuses on the extraction of many quantitative imaging features related to shape, intensity and texture. These features are incorporated into models designed to predict important clinical or biological endpoints for patients. Attention for radiomics research has recently grown dramatically due to the increased use of imaging and the availability of large, publicly available imaging datasets. Glioblastoma multiforme (GBM) patients stand to benefit from this emerging research field as radiomics has the potential to assess the biological heterogeneity of the tumour, which contributes significantly to the inefficacy of current standard of care therapy. Radiomics models still require further development before they are implemented clinically in GBM patient management. Challenges relating to the standardisation of the radiomics process and the validation of radiomic models impede the progress of research towards clinical implementation. In this manuscript, we review the current state of radiomics in GBM, and we highlight the barriers to clinical implementation and discuss future validation studies needed to advance radiomics models towards clinical application.
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Affiliation(s)
- Philip Martin
- Centre for Medical and Radiation Physics, School of Physics, University of Wollongong, Wollongong, NSW 2522, Australia
- Ingham Institute for Applied Medical Research, Liverpool, NSW 2170, Australia
| | - Lois Holloway
- Centre for Medical and Radiation Physics, School of Physics, University of Wollongong, Wollongong, NSW 2522, Australia
- Ingham Institute for Applied Medical Research, Liverpool, NSW 2170, Australia
- Liverpool and Macarthur Cancer Therapy Centres, Liverpool, NSW 2170, Australia
- South Western Sydney Clinical Campus, School of Medicine, University of New South Wales, Liverpool, NSW 2170, Australia
| | - Peter Metcalfe
- Centre for Medical and Radiation Physics, School of Physics, University of Wollongong, Wollongong, NSW 2522, Australia
- Ingham Institute for Applied Medical Research, Liverpool, NSW 2170, Australia
| | - Eng-Siew Koh
- Ingham Institute for Applied Medical Research, Liverpool, NSW 2170, Australia
- Liverpool and Macarthur Cancer Therapy Centres, Liverpool, NSW 2170, Australia
- South Western Sydney Clinical Campus, School of Medicine, University of New South Wales, Liverpool, NSW 2170, Australia
| | - Caterina Brighi
- Ingham Institute for Applied Medical Research, Liverpool, NSW 2170, Australia
- ACRF Image X Institute, Sydney School of Health Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2006, Australia
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Metcalfe P. Residency recruiting: Are virtual open houses here to stay? Can Urol Assoc J 2022; 16:212. [PMID: 35623002 DOI: 10.5489/cuaj.7916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- Peter Metcalfe
- Division of Pediatric Surgery, Department of Surgery, University of Alberta, Edmonton, AB, Canada
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Lawson M, Berk K, Badawy M, Qi Y, Kuganesan A, Metcalfe P. Comparison of organ and effective dose estimations from different Monte Carlo simulation-based software methods in infant CT and comparison with direct phantom measurements. J Appl Clin Med Phys 2022; 23:e13625. [PMID: 35522240 PMCID: PMC9194989 DOI: 10.1002/acm2.13625] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 03/09/2022] [Accepted: 04/11/2022] [Indexed: 11/30/2022] Open
Abstract
Purpose Computational dosimetry software is routinely used to evaluate the organ and effective doses from computed tomography (CT) examinations. Studies have shown a significant variation in dose estimates between software in adult cohorts, and few studies have evaluated software for pediatric dose estimates. This study aims to compare the primary organ and effective doses estimated by four commercially available CT dosimetry software to thermoluminescent dosimeter (TLD) measurements in a 1‐year‐old phantom. Methods One hundred fifteen calibrated LiF (Mg, Cu, P)‐TLD 100‐H chips were embedded within an anthropomorphic phantom representing a 1‐year‐old child at positions that matched the approximate location of organs within an infant. The phantom was scanned under three protocols, each with whole‐body coverage. The mean absorbed doses from 25 radiosensitive organs and skeletal tissues were determined from the TLD readings. Effective doses for each of the protocols were subsequently calculated using ICRP 103 formalism. Dose estimates by the four Monte Carlo–based dose calculation systems were determined and compared to the directly measured doses. Results Most organ doses determined by computation dosimetry software aligned to phantom measurements within 20%. Additionally, comparisons between effective doses are calculated using computational and direct measurement methods aligned within 20% across the three protocols. Significant variances were found in bone surface dose estimations among dosimetry methods, likely caused by differences in bone tissue modeling. Conclusion All four‐dosimetry software evaluated in this study provide adequate primary organ and effective dose estimations. Users should be aware, however, of the possible estimated uncertainty associated with each of the programs.
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Affiliation(s)
- Michael Lawson
- Monash Health Imaging, Monash Health, Clayton, Victoria, Australia.,Centre for Medical Radiation Physics, School of Physics, Faculty of Engineering and Information Sciences, University of Wollongong, Wollongong, New South Wales, Australia
| | - Kemal Berk
- Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
| | - Mohamed Badawy
- Monash Health Imaging, Monash Health, Clayton, Victoria, Australia.,Department of Medical Imaging and Radiation Sciences, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, Australia
| | - Yujin Qi
- Centre for Medical Radiation Physics, School of Physics, Faculty of Engineering and Information Sciences, University of Wollongong, Wollongong, New South Wales, Australia
| | - Ahilan Kuganesan
- Monash Health Imaging, Monash Health, Clayton, Victoria, Australia
| | - Peter Metcalfe
- Centre for Medical Radiation Physics, School of Physics, Faculty of Engineering and Information Sciences, University of Wollongong, Wollongong, New South Wales, Australia
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Carr ME, Keenan KE, Rai R, Boss MA, Metcalfe P, Walker A, Holloway L. Conformance of a 3T Radiotherapy MRI Scanner to the QIBA Diffusion Profile. Med Phys 2022; 49:4508-4517. [PMID: 35365884 PMCID: PMC9543906 DOI: 10.1002/mp.15645] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 03/12/2022] [Accepted: 03/16/2022] [Indexed: 11/11/2022] Open
Abstract
Purpose To assess the technical performance of the apparent diffusion coefficient (ADC) on a dedicated 3T radiotherapy scanner, using a standardized phantom and sequences. Investigations into factors that could impact the technical performance of ADC in the clinic were also completed, including changing the slice‐encoded imaging direction and the reference sample ADC value. Methods ADC acquisitions were performed monthly on an isotropic diffusion phantom over 1 year. Measurements of ADC %bias, coefficients of variation for short‐/long‐term repeatability and precision (CVST/CVLT and CVP), and b‐value dependency (Depb) were calculated. The measurements were then assessed according to the Quantitative Imaging Biomarker Alliance (QIBA) Diffusion Profile specifications. Results The average of all measurements over the year was within Profile recommended ranges. This included when testing was performed in different imaging directions, and on samples that had different ADC reference values (0.4–1.1 μm2/ms). Results in the axial plane for the central water vial included a bias of +0.05%, CVST /CVLT/CVP = 0.1%/ 0.9%/0.4% and Depb = 0.4%. Conclusions The technical performance of ADC on a radiotherapy dedicated MRI scanner over the course of 12 months was considered conformant to the QIBA Profile. Quantifying these metrics and factors that may affect the performance is essential in progressing the use of ADC clinically: ensuring that the observed change of ADC in a tissue is due to a physiological response and not measurement variability.
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Affiliation(s)
- Madeline E Carr
- Centre for Medical and Radiation Physics, University of Wollongong, Wollongong, Australia.,Ingham Institute for Applied Medical Research, Liverpool, Australia.,Liverpool and Macarthur Cancer Therapy Centres, Sydney, Australia
| | - Kathryn E Keenan
- National Institute of Standards and Technology, Boulder, United States
| | - Robba Rai
- Ingham Institute for Applied Medical Research, Liverpool, Australia.,Liverpool and Macarthur Cancer Therapy Centres, Sydney, Australia.,Institute of Medical Physics, University of Sydney, Camperdown, Australia
| | - Michael A Boss
- American College of Radiology, Philadelphia, United States
| | - Peter Metcalfe
- Centre for Medical and Radiation Physics, University of Wollongong, Wollongong, Australia.,Ingham Institute for Applied Medical Research, Liverpool, Australia
| | - Amy Walker
- Centre for Medical and Radiation Physics, University of Wollongong, Wollongong, Australia.,Ingham Institute for Applied Medical Research, Liverpool, Australia.,Liverpool and Macarthur Cancer Therapy Centres, Sydney, Australia.,Institute of Medical Physics, University of Sydney, Camperdown, Australia
| | - Lois Holloway
- Centre for Medical and Radiation Physics, University of Wollongong, Wollongong, Australia.,Ingham Institute for Applied Medical Research, Liverpool, Australia.,Liverpool and Macarthur Cancer Therapy Centres, Sydney, Australia.,Institute of Medical Physics, University of Sydney, Camperdown, Australia.,South Western Sydney Clinical School, University of New South Wales, Liverpool, Australia
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12
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Romao RLP, Braga LH, Keays M, Metcalfe P, Psooy K, Bagli D, Koyle M. Pediatric Urologists of Canada (PUC) 2021 position statement: Differences of sex development (AKA disorders of sex development). Can Urol Assoc J 2021; 15:395-396. [PMID: 34847345 DOI: 10.5489/cuaj.7658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
| | - Luis H Braga
- McMaster's Children's Hospital, Hamilton Health Sciences, Hamilton, ON, Canada
| | - Melise Keays
- Children's Hospital of Eastern Ontario, University of Ottawa, Ottawa, ON, Canada
| | | | - Karen Psooy
- Health Sciences Centre, University of Manitoba, Winnipeg, MB, Canada
| | - Darius Bagli
- Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Martin Koyle
- Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
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13
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Carr ME, Keenan KE, Rai R, Metcalfe P, Walker A, Holloway L. Determining the longitudinal accuracy and reproducibility of T 1 and T 2 in a 3T MRI scanner. J Appl Clin Med Phys 2021; 22:143-150. [PMID: 34562341 PMCID: PMC8598150 DOI: 10.1002/acm2.13432] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 08/17/2021] [Accepted: 09/07/2021] [Indexed: 11/09/2022] Open
Abstract
Purpose To determine baseline accuracy and reproducibility of T1 and T2 relaxation times over 12 months on a dedicated radiotherapy MRI scanner. Methods An International Society of Magnetic Resonance in Medicine/National Institute of Standards and Technology (ISMRM/NIST) System Phantom was scanned monthly on a 3T MRI scanner for 1 year. T1 was measured using inversion recovery (T1‐IR) and variable flip angle (T1‐VFA) sequences and T2 was measured using a multi‐echo spin echo (T2‐SE) sequence. For each vial in the phantom, accuracy errors (%bias) were determined by the relative differences in measured T1 and T2 times compared to reference values. Reproducibility was measured by the coefficient of variation (CV) of T1 and T2 measurements across monthly scans. Accuracy and reproducibility were mainly assessed on vials with relaxation times expected to be in physiological ranges at 3T. Results A strong linear correlation between measured and reference relaxation times was found for all sequences tested (R2 > 0.997). Baseline bias (and CV[%]) for T1‐IR, T1‐VFA and T2‐SE sequences were +2.0% (2.1), +6.5% (4.2), and +8.5% (1.9), respectively. Conclusions The accuracy and reproducibility of T1 and T2 on the scanner were considered sufficient for the sequences tested. No longitudinal trends of variation were deduced, suggesting less frequent measurements are required following the establishment of baselines.
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Affiliation(s)
- Madeline E Carr
- Centre for Medical and Radiation Physics, University of Wollongong, Wollongong, Australia.,Ingham Institute for Applied Medical Research, Liverpool, Australia.,Liverpool and Macarthur Cancer Therapy Centres, Sydney, Australia
| | - Kathryn E Keenan
- National Institute of Standards and Technology, Boulder, Colorado, USA
| | - Robba Rai
- Ingham Institute for Applied Medical Research, Liverpool, Australia.,Liverpool and Macarthur Cancer Therapy Centres, Sydney, Australia.,South Western Sydney Clinical School, University of New South Wales, Liverpool, Australia
| | - Peter Metcalfe
- Centre for Medical and Radiation Physics, University of Wollongong, Wollongong, Australia.,Ingham Institute for Applied Medical Research, Liverpool, Australia
| | - Amy Walker
- Centre for Medical and Radiation Physics, University of Wollongong, Wollongong, Australia.,Ingham Institute for Applied Medical Research, Liverpool, Australia.,Liverpool and Macarthur Cancer Therapy Centres, Sydney, Australia.,South Western Sydney Clinical School, University of New South Wales, Liverpool, Australia
| | - Lois Holloway
- Centre for Medical and Radiation Physics, University of Wollongong, Wollongong, Australia.,Ingham Institute for Applied Medical Research, Liverpool, Australia.,Liverpool and Macarthur Cancer Therapy Centres, Sydney, Australia.,South Western Sydney Clinical School, University of New South Wales, Liverpool, Australia.,Institute of Medical Physics, University of Sydney, Camperdown, Australia
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14
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Cai M, Byrne M, Archibald-Heeren B, Metcalfe P, Rosenfeld A, Wang Y. Reducing axial truncation artifacts in iterative cone-beam CT for radiation therapy using a priori preconditioned information. Med Phys 2021; 48:7089-7098. [PMID: 34554587 DOI: 10.1002/mp.15248] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 07/29/2021] [Accepted: 09/14/2021] [Indexed: 11/06/2022] Open
Abstract
PURPOSE Cone-beam computed tomography (CBCT) is increasingly utilized in radiation therapy for image guidance and adaptive applications. While iterative reconstruction algorithms have been shown to outperform traditional filtered back-projection methods in improving image quality and reducing imaging dose, they cannot handle data truncation in the axial view, which frequently occurs in the full-fan partial-trajectory acquisition mode. This proof-of-concept study presents a novel approach on truncation artifact reduction by utilizing a priori preconditioned information as the initial input for the iterative algorithm. METHODS Projections containing axial truncation were used for image reconstruction in extended axial field-of-view (AFOV) using the conjugate gradient least-squares (CGLS) algorithm. A priori information in the form of a planning fan-beam CT (FBCT) was repositioned in the expected CBCT imaging geometry, then further processed to dampen high-density features and convolved with a cubic Gaussian kernel to ensure differentiability for the gradient descent method. Anatomical and positional differences between the estimated and the actual imaging object were introduced to verify the efficacy of the proposed method. RESULTS Extending the reconstruction AFOV alone could partially reduce truncation artifact. Using a priori information directly resulted in ghosting artifact when there were anatomical and positional differences between the estimated and the actual imaging object. Using a priori preconditioned information was shown to effectively reduce truncation artifact and recover peripheral information. CONCLUSIONS Using a priori preconditioned information can effectively alleviate truncation artifact and assist recovery of peripheral information in iterative CBCT reconstruction.
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Affiliation(s)
- Meng Cai
- Icon Cancer Centre, Wahroonga, Australia.,Centre of Medical and Radiation Physics, University of Wollongong, Wollongong, Australia
| | | | | | - Peter Metcalfe
- Centre of Medical and Radiation Physics, University of Wollongong, Wollongong, Australia
| | - Anatoly Rosenfeld
- Centre of Medical and Radiation Physics, University of Wollongong, Wollongong, Australia
| | - Yang Wang
- Centre of Medical and Radiation Physics, University of Wollongong, Wollongong, Australia.,Icon Cancer Centre, Guangzhou, China
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15
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Lawson M, Tully J, Ditchfield M, Metcalfe P, Qi Y, Kuganesan A, Badawy MK. A review of current imaging techniques used for the detection of occult bony fractures in young children suspected of sustaining non-accidental injury. J Med Imaging Radiat Oncol 2021; 66:68-78. [PMID: 34176229 DOI: 10.1111/1754-9485.13270] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 06/01/2021] [Indexed: 11/30/2022]
Abstract
Non-accidental injuries remain a leading cause of preventable morbidity and mortality in young children. The accurate identification of the full spectrum of injuries in children presenting with suspected abuse is essential to ensure the appropriate protective intervention is taken. The identification of occult bone fractures in this cohort is important as it raises the level of concern about the mechanism of injury and maintaining the child's safety. Radiographic imaging remains the modality of choice for skeletal assessment; however, current studies report concerns regarding the ability of radiographs to detect certain fractures in the acute stage. As such, alternative modalities for the detection of fractures have been proposed. This article reviews the current literature regarding fracture detectability and radiation dose burden of imaging modalities currently used for the assessment of occult bony injury in young children in whom non-accidental injury is suspected.
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Affiliation(s)
- Michael Lawson
- Monash Imaging, Monash Health, Melbourne, Victoria, Australia.,Centre for Medical and Radiation Physics, School of Physics, Faculty of Engineering and Information Sciences, University of Wollongong, Wollongong, New South Wales, Australia
| | - Joanna Tully
- Victorian Forensic Paediatric Medical Service, Monash Children's Hospital, Melbourne, Victoria, Australia
| | - Michael Ditchfield
- Monash Imaging, Monash Health, Melbourne, Victoria, Australia.,Department of Medicine, Monash University, Melbourne, Victoria, Australia
| | - Peter Metcalfe
- Centre for Medical and Radiation Physics, School of Physics, Faculty of Engineering and Information Sciences, University of Wollongong, Wollongong, New South Wales, Australia
| | - Yujin Qi
- Centre for Medical and Radiation Physics, School of Physics, Faculty of Engineering and Information Sciences, University of Wollongong, Wollongong, New South Wales, Australia
| | | | - Mohamed K Badawy
- Monash Imaging, Monash Health, Melbourne, Victoria, Australia.,Department of Medical Imaging and Radiation Sciences, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia
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16
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Madden L, Roberts N, Jelen U, Dong B, Holloway L, Metcalfe P, Rosenfeld A, Li E. In-line MRI-LINAC depth dose measurements using an in-house plastic scintillation dosimeter. Biomed Phys Eng Express 2021; 7. [PMID: 33530066 DOI: 10.1088/2057-1976/abe295] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 02/02/2021] [Indexed: 11/12/2022]
Abstract
Plastic scintillation dosimeters (PSDs) have many properties that make them desirable for relative dosimetry with MRI-LINACs. An in-house PSD, Farmer ionisation chamber and Gafchromic EBT3 film were used to measure central axis percentage depth dose distributions (PDDs) at the Australian MRI-LINAC Mean errors were calculated between each detector's responses, where the in-house PSD was on average within 0.7% of the Farmer chamber and 1.4% of film, while the Farmer chamber and film were on average within 1.1% of each other. However, the PSD systematically over-estimated the dose as depth increased, approaching a maximum overestimation of the order of 3.5% for the smallest field size measured. This trend was statistically insignificant for all other field sizes measured; further investigation is required to determine the source of this effect. The calculated values of mean absolute error are comparable to the those of trusted dosimeters reported in the literature. These mean absolute errors, and the ubiquity of desirable dosimetric qualities inherent to PSDs suggest that PSDs in general are accurate for relative dosimetry with the MRI-LINAC. Further investigation is required into the source of the reported systematic trends dependent on field-size and depth of measurement.
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Affiliation(s)
- Levi Madden
- Centre for Medical Radiation Physics, University of Wollongong, NSW 2522, Australia.,Ingham Institute for Applied Medical Research, Liverpool, NSW 2170, Australia
| | - Natalia Roberts
- Centre for Medical Radiation Physics, University of Wollongong, NSW 2522, Australia.,Ingham Institute for Applied Medical Research, Liverpool, NSW 2170, Australia
| | - Urszula Jelen
- GenesisCare St Vincent's Clinic, Darlinghurst, NSW 2010, Australia
| | - Bin Dong
- Ingham Institute for Applied Medical Research, Liverpool, NSW 2170, Australia
| | - Lois Holloway
- Ingham Institute for Applied Medical Research, Liverpool, NSW 2170, Australia.,Liverpool Cancer Therapy Centre, Liverpool, NSW 2170, Australia.,Macauthur Cancer Therapy Clinic, Campbelltown, NSW 2560, Australia
| | - Peter Metcalfe
- Centre for Medical Radiation Physics, University of Wollongong, NSW 2522, Australia.,Illawarra Medical and Health Research Institute, University of Wollongong, NSW 2522, Australia
| | - Anatoly Rosenfeld
- Centre for Medical Radiation Physics, University of Wollongong, NSW 2522, Australia.,Illawarra Medical and Health Research Institute, University of Wollongong, NSW 2522, Australia
| | - Enbang Li
- Centre for Medical Radiation Physics, University of Wollongong, NSW 2522, Australia
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17
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Muñoz L, Kron T, Petasecca M, Bucci J, Jackson M, Metcalfe P, Rosenfeld AB, Biasi G. Consistency of small-field dosimetry, on and off axis, in beam-matched linacs used for stereotactic radiosurgery. J Appl Clin Med Phys 2021; 22:185-193. [PMID: 33440049 PMCID: PMC7882112 DOI: 10.1002/acm2.13160] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 12/08/2020] [Accepted: 12/17/2020] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Stereotactic radiosurgery (SRS) can be delivered with a standard linear accelerator (linac). At institutions having more than one linac, beam matching is common practice. In the literature, there are indications that machine central axis (CAX) matching for broad fields does not guarantee matching of small fields with side ≤2 cm. There is no indication on how matching for broad fields on axis translates to matching small fields off axis. These are of interest to multitarget single-isocenter (MTSI) SRS planning and the present work addresses that gap in the literature. METHODS We used 6 MV flattening filter free (FFF) beams from four Elekta VersaHD® linacs equipped with an Agility™ multileaf collimator (MLC). The linacs were strictly matched for broad fields on CAX. We compared output factors (OPFs) and effective field size, measured concurrently using a novel 2D solid-state dosimeter "Duo" with a spatial resolution of 0.2 mm, in square and rectangular static fields with sides from 0.5 to 2 cm, either on axis or away from it by 5 to 15 cm. RESULTS Among the four linacs, OPF for fields ≥1 × 1 cm2 ranged 1.3% on CAX, whereas off axis a maximum range of 1.9% was observed at 15 cm. A larger variability in OPF was noted for the 0.5 × 0.5 cm2 field, with a range of 5.9% on CAX, which improved to a maximum of 2.3% moving off axis. Two linacs showed greater consistency with a range of 1.4% on CAX and 2.2% at 15 cm off axis. Between linacs, the effective field size varied by <0.04 cm in most cases, both on and off axis. Tighter matching was observed for linacs with a similar focal spot position. CONCLUSIONS Verification of small-field consistency for matched linacs used for SRS is an important task for dosimetric validation. A significant benefit of concurrent measurement of field size and OPF allowed for a comprehensive assessment using a novel diode array. Our study showed the four linacs, strictly matched for broad fields on CAX, were still matched down to a field size of 1 x 1 cm2 on and off axis.
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Affiliation(s)
- Luis Muñoz
- Genesiscare Flinders Private HospitalBedford ParkSAAustralia
- Centre for Medical Radiation PhysicsUniversity of WollongongNSWAustralia
| | - Tomas Kron
- Centre for Medical Radiation PhysicsUniversity of WollongongNSWAustralia
- Peter MacCallum Cancer CentreMelbourneVICAustralia
| | - Marco Petasecca
- Centre for Medical Radiation PhysicsUniversity of WollongongNSWAustralia
| | - Joseph Bucci
- St. George Cancer Care CentreSt George HospitalKogarahNSWAustralia
- Genesiscare Waratah Private HospitalHurstvilleNSWAustralia
| | - Michael Jackson
- Centre for Medical Radiation PhysicsUniversity of WollongongNSWAustralia
- University of New South WalesKensingtonNSWAustralia
| | - Peter Metcalfe
- Centre for Medical Radiation PhysicsUniversity of WollongongNSWAustralia
| | | | - Giordano Biasi
- Centre for Medical Radiation PhysicsUniversity of WollongongNSWAustralia
- Peter MacCallum Cancer CentreMelbourneVICAustralia
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18
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Haworth A, Fielding AL, Marsh S, Rowshanfarzad P, Santos A, Metcalfe P, Franich R. Will COVID-19 change the way we teach medical physics post pandemic? Phys Eng Sci Med 2020; 43:735-738. [PMID: 32720293 PMCID: PMC7383115 DOI: 10.1007/s13246-020-00898-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- A Haworth
- School of Physics, University of Sydney, Sydney, Australia.
| | - A L Fielding
- Science & Engineering Faculty, Queensland University of Technology, Brisbane, Australia
| | - S Marsh
- School of Physical and Chemical Sciences, University of Canterbury, Christchurch, New Zealand
| | - P Rowshanfarzad
- Department of Physics, University of Western Australia, Perth, Australia
| | - A Santos
- School of Physical Sciences, University of Adelaide, Adelaide, Australia.,Department of Medical Physics, Royal Adelaide Hospital, Adelaide, Australia
| | - P Metcalfe
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, Australia
| | - R Franich
- School of Science, RMIT University, Melbourne, Australia
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19
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Cai M, Byrne M, Archibald-Heeren B, Metcalfe P, Rosenfeld A, Wang Y. Decoupling of bowtie and object effects for beam hardening and scatter artefact reduction in iterative cone-beam CT. Phys Eng Sci Med 2020; 43:1161-1170. [PMID: 32813233 DOI: 10.1007/s13246-020-00918-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 08/06/2020] [Indexed: 11/28/2022]
Abstract
Cone-beam computed tomography (CBCT) is an important imaging modality for image-guided radiotherapy and adaptive radiotherapy. Feldkamp-Davis-Kress (FDK) method is widely adopted in clinical CBCT reconstructions due to its fast and robust application. While iterative algorithms have been shown to outperform FDK techniques in reducing noise and imaging dose, they are unable to correct projection-domain artefacts such as beam hardening and scatter. Empirical correction techniques require a holistic approach as beam hardening and scatter coexist in the measurement data. This multi-part proof of concept study conducted in MATLAB presents a novel approach to artefact reduction for CBCT image reconstruction. Firstly, we decoupled the beam hardening and scatter contributions originating from the imaging object and the bowtie filter. Next, a model was constructed to apply pixel-wise corrections to separately account for artefacts induced by the imaging object and the bowtie filter, in order to produce mono-energetic equivalent and scatter-compensated projections. Finally, the effectiveness of the correction model was tested on an offset phantom scan as well as a clinical brain scan. A conjugate-gradient least-squares algorithm was implemented over five iterations using FDK result as the initial input. Our proposed correction model was shown to effectively reduce cupping and shading artefacts in both phantom and clinical studies. This simple yet effective correction model could be readily implemented by physicists seeking to explore the benefits of iterative reconstruction.
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Affiliation(s)
- Meng Cai
- Icon Cancer Centre, Wahroonga, Australia. .,Centre of Medical and Radiation Physics, University of Wollongong, Wollongong, Australia.
| | | | | | - Peter Metcalfe
- Centre of Medical and Radiation Physics, University of Wollongong, Wollongong, Australia
| | - Anatoly Rosenfeld
- Centre of Medical and Radiation Physics, University of Wollongong, Wollongong, Australia
| | - Yang Wang
- Centre of Medical and Radiation Physics, University of Wollongong, Wollongong, Australia.,Icon Cancer Centre, Guangzhou, China
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20
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Kron T, Metcalfe P, Baldock C. Should ACPSEM develop its own position papers or just adopt those of the AAPM? Phys Eng Sci Med 2020; 43:749-753. [PMID: 32696436 PMCID: PMC7373210 DOI: 10.1007/s13246-020-00900-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Tomas Kron
- Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, VIC 3000 Australia
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2500 Australia
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, VIC 3010 Australia
| | - Peter Metcalfe
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2500 Australia
| | - Clive Baldock
- School of Engineering, College of Science and Engineering, University of Tasmania, Sandy Bay, TAS 7005 Australia
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21
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Hoare DT, Metcalfe P. An epidemiologic overview of a tertiary referral practice for male paediatric lichen sclerosus. Paediatr Child Health 2020; 25:241-245. [PMID: 32549740 DOI: 10.1093/pch/pxy172] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2018] [Accepted: 09/06/2018] [Indexed: 11/15/2022] Open
Abstract
Within the paediatric population, changing patterns of circumcisions have confounded the epidemiology and presentation of lichen sclerosus (LS). We sought to evaluate the incidence, demographics, and clinical features of patients presenting to a single Albertan paediatric urologist with LS. This retrospective descriptive analysis evaluated all paediatric patients referred for phimosis to a single paediatric urologist in Edmonton, Alberta. Chief complaints/symptoms, date of birth, and date of circumcision were identified. The primary outcome of interest was the proportion of circumcisions with pathologically confirmed LS. From July 2006 to March 2016, 4,163 patients were seen for phimosis of the approximate 12,000 new referrals. Hundred phimosis patients had clinically suspected LS. Of those adequately reported, 81 (81/83) were microscopically confirmed to be LS with a mean age of 9.6 years and median age of 8.9 years (range 4.1 to 16.1 years). This cohort represented 2.0% of phimosis referrals and approximately 0.7% of all referrals to our paediatric urologist. When compared to physiologic phimosis, these patients had higher rates of dysuria (n=28, 34.6% versus n=1, 1.0%, P<0.0001) and urinary retention (n=18, 22.2% versus n=1, 1.0%, P<0.0001) as presenting complaints. LS of the paediatric male genitalia is an uncommon, albeit clinically significant disease entity. The clinical diagnosis for the trained practitioner is very accurate.
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Affiliation(s)
- Dylan Thomas Hoare
- Division of Urology, Department of Surgery, University of Alberta, Edmonton, Alberta
| | - Peter Metcalfe
- Division of Urology, Department of Surgery, University of Alberta, Edmonton, Alberta.,Division of Pediatric Surgery, Department of Surgery, Stollery Children's Hospital, University of Alberta, Edmonton, Alberta
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22
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Nettey OS, Bowen DK, Santiago-Lastra Y, Metcalfe P, Kielb SJ. Complications in adulthood for patients with paediatric genitourinary reconstruction. World J Urol 2020; 39:1029-1036. [PMID: 32529452 DOI: 10.1007/s00345-020-03295-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Accepted: 06/03/2020] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Caring for adults with prior paediatric genitourinary reconstruction remains a challenge for adult providers. Reconstructions typically have occurred decades before; surgical records are not always available and patients and families may be unable to convey procedures performed. Spina bifida (SB) patients are vulnerable to cognitive decline which may compound these challenges. Changes in patient body habitus and loss of function may contribute to problems with previous reconstructions. METHODS This is a non-systematic review of the literature and represents expert opinion where data are non-existent. This review focuses on the evaluation and management of complications arising from genitourinary reconstruction in congenital neurogenic bladder patients. RESULTS Common complications experienced by congenital neurogenic bladder patients include recurrent urinary tract infection, incontinence of catheterizable channel and urinary reservoir as well as malignancy as this population ages. Preservation of renal function and prevention of urinary tract infection while optimizing continence are essential guiding principles in the care of these patients. Many of the recommendations, however, are gleaned from available data in the adult spinal cord patient (a more commonly studied population) or the paediatric urologic literature due to limited studies in adult management of such patients. CONCLUSION Close follow-up and vigilance is warranted to monitor for infectious, mechanical and malignant complications while optimizing preservation of the upper urinary tracts and patient quality of life.
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Affiliation(s)
- Oluwarotimi S Nettey
- Department of Urology, Northwestern University Feinberg School of Medicine, 676 N. St. Clair, Arkes 23rd floor, Chicago, IL, 60611, USA.
| | - Diana K Bowen
- Department of Adult and Pediatric Urology, Lurie Children's Hospital, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
| | - Yahir Santiago-Lastra
- Department of Urology, University of Southern California San Diego, San Diego, CA, USA
| | - Peter Metcalfe
- Department of Surgery, Division of Pediatric Surgery, University of Alberta, Alberta, Canada
| | - Stephanie J Kielb
- Department of Urology, Gynecology, and Medical Education, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
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23
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Alnaghy SJ, Causer T, Roberts N, Oborn B, Jelen U, Dong B, Gargett M, Begg J, Liney G, Petasecca M, Rosenfeld AB, Holloway L, Metcalfe P. High resolution silicon array detector implementation in an inline MRI-linac. Med Phys 2020; 47:1920-1929. [PMID: 31917865 DOI: 10.1002/mp.14016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 01/06/2020] [Accepted: 01/07/2020] [Indexed: 11/09/2022] Open
Abstract
PURPOSE Dynamic dosimaging is a concept whereby a detector in motion is tracked with magnetic resonance imaging (MRI) to validate the amount and position of dose in a radiation therapy treatment on an MRI-linac. This work takes steps toward the realization of dynamic dosimaging with the novel high resolution silicon array detector: MagicPlate-512 (M512). The performance of the M512 was assessed in a 1.0 T inline MRI-linac, without simultaneous imaging and then during an imaging sequence, both during dosimetry. MR images were acquired to determine the effect of the detector and its components on image quality. METHODS Beam profiles were measured using the M512 on the Australian MRI-Linac and a comparison made with Gafchromic EBT3 film to investigate any intrinsic magnetic field effects in the silicon. The M512 has 512 sensitive volumes, each 0.5 × 0.5 × 0.037 mm3 in dimension, organized in a two-dimensional array. Small field sizes up to 4.2 × 3.8 cm2 were investigated in both solid water and then solid lung phantoms. Beam profiles taken at 1.0 T were compared to 0 T conditions, and also to profiles taken during a gradient echo (GRE) imaging sequence. Differences in 80%-20% penumbral width and full width at half maximum (FWHM) were investigated. Localizer MR images were acquired of the detector adjacent to a water phantom. RESULTS Good agreement was observed between the M512 and film, with average differences in penumbral width and FWHM of <1 mm in the absence of the imaging sequence. Concurrent imaging widened the penumbra by up to 1.2 mm due to RF noise affecting the detector; film profiles were unchanged. Magnetic resonance images were affected by noise, in particular, due to the large amount of aluminum present, as well as from the USB cable, which acted as an antenna. Unfortunately, due to these issues, suitable dynamic dose imaging was not achieved with the current M512/phantom configuration and the MRI-linac. However, progress was made toward achieving this goal for future work. CONCLUSIONS The M512 silicon array detector successfully measured high-resolution beam profiles in agreement with Gafchromic film to within an average of <1 mm on the first MRI-linac in Australia. More effective noise reduction will be required for the achievement of dynamic dosimaging in the future.
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Affiliation(s)
- Sarah J Alnaghy
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia.,Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia
| | - Trent Causer
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia.,Illawarra Cancer Care Centre, Wollongong Hospital, Wollongong, NSW, 2500, Australia
| | - Natalia Roberts
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia.,Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia
| | - Brad Oborn
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia.,Illawarra Cancer Care Centre, Wollongong Hospital, Wollongong, NSW, 2500, Australia
| | - Urszula Jelen
- Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia.,Department of Medical Physics, Liverpool and Macarthur Cancer Therapy Centre, Liverpool, NSW, 2170, Australia
| | - Bin Dong
- Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia.,Department of Medical Physics, Liverpool and Macarthur Cancer Therapy Centre, Liverpool, NSW, 2170, Australia
| | - Maegan Gargett
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia.,Northern Sydney Cancer Centre, Royal North Shore Hospital, St. Leonards, NSW, 2065, Australia
| | - Jarrad Begg
- Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia.,Department of Medical Physics, Liverpool and Macarthur Cancer Therapy Centre, Liverpool, NSW, 2170, Australia.,South Western Sydney Clinical School, University of New South Wales, Liverpool, NSW, 2170, Australia
| | - Gary Liney
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia.,Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia.,Department of Medical Physics, Liverpool and Macarthur Cancer Therapy Centre, Liverpool, NSW, 2170, Australia.,South Western Sydney Clinical School, University of New South Wales, Liverpool, NSW, 2170, Australia
| | - Marco Petasecca
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Anatoly B Rosenfeld
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Lois Holloway
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia.,Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia.,Illawarra Cancer Care Centre, Wollongong Hospital, Wollongong, NSW, 2500, Australia.,Department of Medical Physics, Liverpool and Macarthur Cancer Therapy Centre, Liverpool, NSW, 2170, Australia.,South Western Sydney Clinical School, University of New South Wales, Liverpool, NSW, 2170, Australia.,Institute of Medical Physics, University of Sydney, Camperdown, NSW, 2505, Australia
| | - Peter Metcalfe
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia.,Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia
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Albers P, Shafey A, Assmus M, Metcalfe P. AUTHOR REPLY. Urology 2020; 135:138. [PMID: 31895677 DOI: 10.1016/j.urology.2019.07.051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 07/30/2019] [Indexed: 10/25/2022]
Affiliation(s)
- P Albers
- Faculty of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - A Shafey
- Department of Pediatrics, Stollery Children's Hospital, Edmonton, Alberta, Canada
| | - M Assmus
- Department of Surgery, Division of Urology, University of Alberta, Edmonton, Alberta, Canada
| | - P Metcalfe
- Department of Surgery, Division of Urology, University of Alberta, Edmonton, Alberta, Canada
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Jameson M, Martin P, Aly F, Koh E, Rai R, Estall V, Liney G, Metcalfe P, Holloway L. OC-024: Changes in brain tumour perfusion and diffusion characteristic during treatment. Radiother Oncol 2019. [DOI: 10.1016/s0167-8140(20)30430-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Roberts NF, Williams M, Holloway L, Metcalfe P, Oborn BM. 4D Monte Carlo dose calculations for pre-treatment quality assurance of VMAT SBRT: a phantom-based feasibility study. Phys Med Biol 2019; 64:21NT01. [PMID: 31470421 DOI: 10.1088/1361-6560/ab3fd0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Volumetric arc therapy (VMAT) for lung stereotactic body radiotherapy (SBRT) is challenging due to both breathing-induced motion and the dynamic components of the linear accelerator. In this study, a 4D Monte Carlo (4DMC) dose calculation method for VMAT SBRT is proposed and the feasibility of the method is evaluated. A rigidly-moving lung phantom was imaged using four dimensional computed tomography (4DCT). VMAT SBRT plans were generated on the average intensity projection dataset using the internal target volume (ITV) strategy (ITV-plan) and a single phase to simulate a dynamic treatment-couch tracking technique (TRACKING-plan). 4DMC simulations were performed and compared to 3D Monte Carlo (3DMC) and 3D- and 4D- calculations in the treatment planning system using the adaptive convolution (AC) algorithm. Dose metrics calculated for the ITV-plan showed an overestimation with 3D adaptive convolution (3DAC) for D[Formula: see text] (GTV) by 3.5% and by 2.0% for 3DMC, both compared to 4DMC. The TRACKING-plan D[Formula: see text] (GTV) calculated with the 3DAC method overestimated by 2.0% compared with 4DMC. Deviations between the calculation methods for D mean (Lung) and D[Formula: see text] (PTV) were minimal. For both plans, measurements were taken with EBT3 film inside the phantom tumour. EBT3 film profiles showed good agreement with 4DMC for the TRACKING-plan giving a gamma pass rate of 97.2% for 3%/3 mm global and for 3DAC compared with measured, 95.8%. Whereas for the ITV-plan, the 3D profiles varied from film in the ITV periphery region with a pass rates of 50% and 48.6% for 3DAC and 3DMC, respectively. 4DMC agreed more closely to measurements for this plan with a pass rate of 95.8%. We have proposed an accurate method to perform 4D dose calculations for pre-treatment quality assurance of VMAT SBRT. The method was compared to experimental measurements and for both plans, 4DMC dose agreed with measurements more closely than other evaluated dose calculation methods. This study has demonstrated the feasibility of this 4DMC method.
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Affiliation(s)
- Natalia F Roberts
- Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, NSW, Australia. Centre for Oncology Education and Research Translation (CONCERT), Wollongong, NSW, Australia. Ingham Institute for Applied Medical Research, Liverpool, NSW, Australia. Author to whom correspondence should be addressed
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27
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Roberts NF, Patterson E, Jelen U, Causer T, Holloway L, Liney G, Lerch M, Rosenfeld AB, Cutajar D, Oborn BM, Metcalfe P. Experimental characterization of magnetically focused electron contamination at the surface of a high-field inline MRI-linac. Med Phys 2019; 46:5780-5789. [PMID: 31633212 DOI: 10.1002/mp.13847] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 08/26/2019] [Accepted: 09/23/2019] [Indexed: 11/08/2022] Open
Abstract
PURPOSE The fringe field of the Australian MRI-linac causes contaminant electrons to be focused along the central axis resulting in a high surface dose. This work aims to characterize this effect using Gafchromic film and high-resolution detectors, MOSkinTM and microDiamond. The secondary aim is to investigate the influence of the inline magnetic field on the relative dose response of these detectors. METHODS The Australian MRI-linac has the unique feature that the linac is mounted on rails allowing for measurements to be performed at different magnetic field strengths while maintaining a constant source-to-surface distance (SSD). Percentage depth doses (PDD) were collected at SSD 1.82 m in a solid water phantom positioned in a low magnetic field region and then at isocenter of the MRI where the magnetic field is 1 T. Measurements for a range of field sizes were taken with the MOSkinTM , microDiamond, and Gafchromic® EBT3 film. The detectors' relative responses at 1 T were compared to the near 0 T PDD beyond the region of electron contamination, that is, 20 mm depth. The near surface measurements inside the MRI bore were compared among the different detectors. RESULTS Skin dose in the MRI, as measured with the MOSkinTM , was 104.5% for 2.1 × 1.9 cm2 , 185.6% for 6.1 × 5.8 cm2 , 369.1% for 11.8 × 11.5 cm2 , and 711.1% for 23.5 × 23 cm2 . The detector measurements beyond the electron contamination region showed agreement between the relative response at 1 T and near 0 T. Film was in agreement with both detectors in this region further demonstrating their relative response is unaffected by the magnetic field. CONCLUSIONS Experimental characterization of the high electron contamination at the surface was performed for a range of field sizes. The relative response of MOSkinTM and microDiamond detectors, beyond the electron contamination region, were confirmed to be unaffected by the 1-T inline magnetic field.
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Affiliation(s)
- Natalia F Roberts
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia.,Centre for Oncology Education and Research Translation, Wollongong, NSW, 2522, Australia.,Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia
| | - Elizabeth Patterson
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Urszula Jelen
- Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia
| | - Trent Causer
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia.,Illawarra Cancer Care Centre, Wollongong Hospital, Wollongong, NSW, 2500, Australia
| | - Lois Holloway
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia.,Centre for Oncology Education and Research Translation, Wollongong, NSW, 2522, Australia.,Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia.,Department of Medical Physics, Liverpool and Macarthur Cancer Care Centres, Liverpool, NSW, 2170, Australia.,South Western Sydney Clinical School, University of New South Wales, Liverpool, NSW, Australia.,Institute of Medical Physics, University of Sydney, Camperdown, NSW, 2505, Australia
| | - Gary Liney
- Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia
| | - Michael Lerch
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Anatoly B Rosenfeld
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Dean Cutajar
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Bradley M Oborn
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia.,Illawarra Cancer Care Centre, Wollongong Hospital, Wollongong, NSW, 2500, Australia
| | - Peter Metcalfe
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia.,Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia
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Albers P, Shafey A, Assmus M, Metcalfe P. Witnessed Torsion in Extremely Premature Newborns: 2 Cases of Testicular Salvage in the NICU. Urology 2019; 135:136-138. [PMID: 31568794 DOI: 10.1016/j.urology.2019.07.048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/26/2019] [Accepted: 07/30/2019] [Indexed: 10/25/2022]
Abstract
Neonatal testicular torsion is an uncommon event that rarely results in testicular salvage. We present 2 cases in the neonatal intensive care unit of extremely premature males (<28 weeks gestation) with witnessed testicular torsion, prompt diagnosis, surgical detorsion, and good short-term outcomes. Although an uncommon scenario, we present the feasibility of surgery in the extremely premature infant and potential for testicular salvage.
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Affiliation(s)
- Patrick Albers
- Faculty of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Amy Shafey
- Department of Pediatrics, Stollery Children's Hospital, Edmonton, Alberta, Canada
| | - Mark Assmus
- Department of Surgery, Division of Urology, University of Alberta, Edmonton, Alberta, Canada
| | - Peter Metcalfe
- Department of Surgery, Division of Urology, University of Alberta, Edmonton, Alberta, Canada.
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Alnaghy SJ, Causer T, Gargett M, Roberts N, Petasecca M, Oborn BM, Rosenfeld AB, Holloway L, Metcalfe P. A feasibility study for high-resolution silicon array detector performance in the magnetic field of a permanent magnet system. Med Phys 2019; 46:4224-4232. [PMID: 31246282 DOI: 10.1002/mp.13686] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 05/27/2019] [Accepted: 06/17/2019] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Magnetic field effects on dose distribution and detector functionality must be well understood. The detector utilized to investigate these magnetic field effects was the DUO silicon array detector; the performance of this high spatial resolution detector was assessed under these conditions. The results were compared to Gafchromic EBT3 film to highlight any intrinsic magnetic field effects in the silicon. The results were also compared to previously published MagicPlate-512 (M512) data. The DUO has an improved spatial resolution (200 µm) over the M512 (2 mm). METHODS A permanent magnet named Magnetic Apparatus for RaDiation Oncology Studies (MARDOS) paired with a standard linear accelerator (linac) enables either transverse (1.2 T) or inline (0.95 T) orientations of the magnetic field with respect to the radiation beam. A 6 MV Varian 2100C Linac provided the radiation component for the measurements. The DUO detector has 505 sensitive volumes (each volume measuring 800 × 40 × 100 µm3 ) organized in two orthogonal, linear arrays. The DUO was embedded in a solid water phantom in the first set-up and then a solid lung phantom in the second set-up and placed between the magnet cones. Beam profiles were compared under the magnetic field conditions and 0 T. Small field sizes from 0.8 × 0.8 cm2 up to 2.3 × 2.3 cm2 were investigated. The size of the air gap above the sensitive volumes of the DUO was investigated in the transverse orientation to assess the anticipated magnetic field effects. Full width at half maximum (FWHM), 80-20% penumbral widths and maximum dose differences between detectors and between the presence/absence of a magnetic field were investigated. Symmetry was also assessed for investigation of profile skewness under the transverse field. RESULTS The penumbral widths measured by the DUO detector demonstrated good agreement with film and the M512 to within an average of 0.5 mm (within uncertainty: ±1 mm). The static inline magnetic field had minimal effect on the profiles in solid water. As expected, the lower density of solid lung meant that this material was more susceptible to demonstrating magnetic field effects in the dose deposited. The greatest penumbral narrowing due to the inline field (0.7 mm) occurred in lung. Central axis dose increase was greatest in lung (maximum: 9%). The transverse field widened penumbra, most notably in the solid lung phantom, by a maximum of 2.3 mm. The largest asymmetry due to the transverse field (4.6%) was also in solid lung. When the air gap above the DUO was filled with bolus, the dose maximum measured by the DUO was within 1.4% of film. CONCLUSIONS The DUO detector has been shown to be successful in accurately describing the dose changes for small field sizes to within a 200-µm resolution in an environment resembling that of an MRI-linac. The DUO measurements were in agreement with both film and the M512 measurements, and therefore the DUO was found to be an appropriate alternative to the M512, with improvement in terms of its higher spatial resolution. MARDOS provided a suitable environment for these preliminary tests before progressing to the MRI-linac.
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Affiliation(s)
- Sarah J Alnaghy
- Centre for Medical Radiation Physics, University of Wollongong, New South Wales (NSW), Wollongong, 2522, Australia.,Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia
| | - Trent Causer
- Centre for Medical Radiation Physics, University of Wollongong, New South Wales (NSW), Wollongong, 2522, Australia.,Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia.,Illawarra Cancer Care Centre, Wollongong Hospital, Wollongong, NSW, 2500, Australia
| | - Maegan Gargett
- Centre for Medical Radiation Physics, University of Wollongong, New South Wales (NSW), Wollongong, 2522, Australia.,Northern Sydney Cancer Centre, Royal North Shore Hospital, St. Leonards, NSW, 2065, Australia
| | - Natalia Roberts
- Centre for Medical Radiation Physics, University of Wollongong, New South Wales (NSW), Wollongong, 2522, Australia.,Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia
| | - Marco Petasecca
- Centre for Medical Radiation Physics, University of Wollongong, New South Wales (NSW), Wollongong, 2522, Australia
| | - Brad M Oborn
- Centre for Medical Radiation Physics, University of Wollongong, New South Wales (NSW), Wollongong, 2522, Australia.,Illawarra Cancer Care Centre, Wollongong Hospital, Wollongong, NSW, 2500, Australia
| | - Anatoly B Rosenfeld
- Centre for Medical Radiation Physics, University of Wollongong, New South Wales (NSW), Wollongong, 2522, Australia
| | - Lois Holloway
- Centre for Medical Radiation Physics, University of Wollongong, New South Wales (NSW), Wollongong, 2522, Australia.,Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia.,Illawarra Cancer Care Centre, Wollongong Hospital, Wollongong, NSW, 2500, Australia.,Department of Medical Physics, Liverpool and Macarthur Cancer Therapy Centre, Liverpool, NSW, 2170, Australia.,South Western Sydney Clinical School, University of New South Wales, Liverpool, NSW, 2170, Australia.,Institute of Medical Physics, University of Sydney, Camperdown, NSW, 2505, Australia.,Central Clinical School, University of Sydney, Camperdown, NSW, 2505, Australia
| | - Peter Metcalfe
- Centre for Medical Radiation Physics, University of Wollongong, New South Wales (NSW), Wollongong, 2522, Australia.,Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia
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Stansook N, Biasi G, Utitsarn K, Petasecca M, Metcalfe P, Carolan M, Lerch MLF, Perevertaylo VL, Kron T, Rosenfeld AB. 2D monolithic silicon-diode array detectors in megavoltage photon beams: does the fabrication technology matter? A medical physicist's perspective. Australas Phys Eng Sci Med 2019. [PMID: 30790139 DOI: 10.1007/s13246-019-00736-7/figures/10] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
Abstract
A family of prototype 2D monolithic silicon-diode array detectors (MP512, Duo, Octa) has been proposed by the Centre for Medical Radiation Physics, University of Wollongong (Australia) for relative dosimetry in small megavoltage photon beams. These detectors, which differ in the topology of their 512 sensitive volumes, were originally fabricated on bulk p-type substrates. More recently, they have also been fabricated on epitaxial p-type substrates. In the literature, their performance has been individually characterized for quality assurance (QA) applications. The present study directly assessed and compared that of a MP512-bulk and that of a MP512-epitaxial in terms of radiation hardness, long-term stability, response linearity with dose, dose per pulse and angular dependence. Their measurements of output factors, off-axis ratios and percentage depth doses in square radiation fields collimated by the jaws and produced by 6 MV and 10 MV flattened photon beams were then benchmarked against those by commercially available detectors. The present investigation was aimed at establishing, from a medical physicist's perspective, how the bulk and epitaxial fabrication technologies would affect the implementation of the MP512s into a QA protocol. Based on results, the MP512-epitaxial would offer superior radiation hardness, long-term stability and achievable uniformity and reproducibility of the response across the 2D active area.
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Affiliation(s)
- N Stansook
- Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, Australia
- Department of Radiology, Faculty of Medicine, Mahidol University, Bangkok, Thailand
| | - G Biasi
- Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, Australia
| | - K Utitsarn
- Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, Australia
- Department of Medical Services, Lopburi Cancer Hospital, Lopburi, Thailand
| | - M Petasecca
- Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, Australia
- Illawarra Health and Medical Research Institute (IHMRI), Wollongong, Australia
| | - P Metcalfe
- Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, Australia
| | - M Carolan
- Illawarra Health and Medical Research Institute (IHMRI), Wollongong, Australia
- Illawarra Cancer Care Centre (ICCC), Wollongong, Australia
| | - M L F Lerch
- Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, Australia
- Illawarra Health and Medical Research Institute (IHMRI), Wollongong, Australia
| | | | - T Kron
- Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, Australia
- Peter MacCallum Cancer Centre, Melbourne, Australia
- Sir Peter MacCallum Cancer Institute, University of Melbourne, Melbourne, Australia
| | - A B Rosenfeld
- Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, Australia.
- Illawarra Health and Medical Research Institute (IHMRI), Wollongong, Australia.
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Dyce E, Cutajar D, Metcalfe P, Downes S. Dose verification for liver target volumes undergoing respiratory motion. Australas Phys Eng Sci Med 2019; 42:619-626. [PMID: 31049839 DOI: 10.1007/s13246-019-00737-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 02/19/2019] [Indexed: 10/26/2022]
Abstract
Respiratory motion has a significant impact on dose delivered to abdominal targets during radiotherapy treatment. Accurate treatment of liver tumours adjacent to the diaphragm is complicated by large respiratory movement, as well as differing tissue densities at the lung-liver interface. This study aims to evaluate the accuracy of dose delivered to superior liver tumours using passive respiratory monitoring, in the absence of gating technology, for a range of treatment techniques. An in-house respiratory phantom was designed and constructed to simulate the lung and liver anatomy. The phantom consisted of adjacent slabs of lung and liver equivalent materials and a cam drive system to emulate respiratory motion. A CC04 ionisation chamber and Gafchromic EBT3 film were used to perform point dose and dose plane measurements respectively. Plans were calculated using an Elekta Monaco treatment planning system (TPS) on exhale phase study sets for conformal, volume modulated arc therapy (VMAT) and intensity modulated radiation therapy (IMRT) techniques, with breathing rates of 8, 14 and 23 bpm. Analysis confirmed the conformal delivery protocol currently used for this site within the department is suitable. The experiments also determined that VMAT is a viable alternative technique for treatment of superior liver lesions undergoing respiratory motion and was superior to IMRT. Furthermore, the measurements highlighted the need for respiratory management in these cases. Displacements due to respiration exceeding planned margins could result in reduced coverage of the clinical target volume and much higher doses to the lung than anticipated.
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Affiliation(s)
- Emma Dyce
- Nelune Comprehensive Cancer Centre, Prince of Wales Hospital, Sydney, Australia.
| | - Dean Cutajar
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, Australia
| | - Peter Metcalfe
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, Australia
| | - Simon Downes
- Nelune Comprehensive Cancer Centre, Prince of Wales Hospital, Sydney, Australia
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32
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Brace O, Alhujali S, Deshpande S, Vial P, Metcalfe P, Lerch M, Petasecca M, Rosenfeld A. EP-1753 A dual detector system for in-vivo dosimetry: transit dose verification and error identification. Radiother Oncol 2019. [DOI: 10.1016/s0167-8140(19)32173-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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33
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Stansook N, Biasi G, Utitsarn K, Petasecca M, Metcalfe P, Carolan M, Lerch MLF, Perevertaylo VL, Kron T, Rosenfeld AB. 2D monolithic silicon-diode array detectors in megavoltage photon beams: does the fabrication technology matter? A medical physicist's perspective. Australas Phys Eng Sci Med 2019; 42:443-451. [PMID: 30790139 DOI: 10.1007/s13246-019-00736-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 02/19/2019] [Indexed: 01/24/2023]
Abstract
A family of prototype 2D monolithic silicon-diode array detectors (MP512, Duo, Octa) has been proposed by the Centre for Medical Radiation Physics, University of Wollongong (Australia) for relative dosimetry in small megavoltage photon beams. These detectors, which differ in the topology of their 512 sensitive volumes, were originally fabricated on bulk p-type substrates. More recently, they have also been fabricated on epitaxial p-type substrates. In the literature, their performance has been individually characterized for quality assurance (QA) applications. The present study directly assessed and compared that of a MP512-bulk and that of a MP512-epitaxial in terms of radiation hardness, long-term stability, response linearity with dose, dose per pulse and angular dependence. Their measurements of output factors, off-axis ratios and percentage depth doses in square radiation fields collimated by the jaws and produced by 6 MV and 10 MV flattened photon beams were then benchmarked against those by commercially available detectors. The present investigation was aimed at establishing, from a medical physicist's perspective, how the bulk and epitaxial fabrication technologies would affect the implementation of the MP512s into a QA protocol. Based on results, the MP512-epitaxial would offer superior radiation hardness, long-term stability and achievable uniformity and reproducibility of the response across the 2D active area.
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Affiliation(s)
- N Stansook
- Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, Australia.,Department of Radiology, Faculty of Medicine, Mahidol University, Bangkok, Thailand
| | - G Biasi
- Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, Australia
| | - K Utitsarn
- Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, Australia.,Department of Medical Services, Lopburi Cancer Hospital, Lopburi, Thailand
| | - M Petasecca
- Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, Australia.,Illawarra Health and Medical Research Institute (IHMRI), Wollongong, Australia
| | - P Metcalfe
- Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, Australia
| | - M Carolan
- Illawarra Health and Medical Research Institute (IHMRI), Wollongong, Australia.,Illawarra Cancer Care Centre (ICCC), Wollongong, Australia
| | - M L F Lerch
- Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, Australia.,Illawarra Health and Medical Research Institute (IHMRI), Wollongong, Australia
| | | | - T Kron
- Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, Australia.,Peter MacCallum Cancer Centre, Melbourne, Australia.,Sir Peter MacCallum Cancer Institute, University of Melbourne, Melbourne, Australia
| | - A B Rosenfeld
- Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, Australia. .,Illawarra Health and Medical Research Institute (IHMRI), Wollongong, Australia.
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Alnaghy SJ, Begg J, Causer T, Alharthi T, Glaubes L, Dong B, George A, Holloway L, Metcalfe P. Erratum: "Technical Note: Penumbral Width Trimming in Solid Lung Dose Profiles for 0.9 T and 1.5 T MRI-Linac Prototypes" [Med. Phys. 45(1), 479-487 (2018)]. Med Phys 2018; 45:4783-4787. [PMID: 30307632 DOI: 10.1002/mp.13117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Sarah J Alnaghy
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia.,Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia
| | - Jarrad Begg
- Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia.,Department of Medical Physics, Liverpool and Macarthur Cancer Therapy Centre, Liverpool, NSW, 2170, Australia.,South Western Sydney Clinical School, University of New South Wales, Liverpool, NSW, 2170, Australia
| | - Trent Causer
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia.,Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia.,Illawarra Cancer Care Centre, Wollongong Hospital, Wollongong, NSW, 2500, Australia
| | - Thahabah Alharthi
- Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia.,Institute of Medical Physics, University of Sydney, Camperdown, NSW, 2505, Australia
| | - Laura Glaubes
- Institute of Medical Physics, University of Sydney, Camperdown, NSW, 2505, Australia
| | - Bin Dong
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia.,Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia.,Department of Medical Physics, Liverpool and Macarthur Cancer Therapy Centre, Liverpool, NSW, 2170, Australia
| | - Armia George
- Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia.,Department of Medical Physics, Liverpool and Macarthur Cancer Therapy Centre, Liverpool, NSW, 2170, Australia
| | - Lois Holloway
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia.,Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia.,Department of Medical Physics, Liverpool and Macarthur Cancer Therapy Centre, Liverpool, NSW, 2170, Australia.,South Western Sydney Clinical School, University of New South Wales, Liverpool, NSW, 2170, Australia.,Institute of Medical Physics, University of Sydney, Camperdown, NSW, 2505, Australia.,Sydney Medical School, University of Sydney, Camperdown, NSW, 2505, Australia
| | - Peter Metcalfe
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, 2522, Australia.,Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia
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Al-Rahbi ZS, Cutajar DL, Metcalfe P, Rosenfeld AB. Dosimetric effects of brass mesh bolus on skin dose and dose at depth for postmastectomy chest wall irradiation. Phys Med 2018; 54:84-93. [DOI: 10.1016/j.ejmp.2018.09.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 09/21/2018] [Indexed: 11/28/2022] Open
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Gargett M, Oborn B, Alnaghy SJ, Causer T, Petasecca M, Rosenfeld AB, Metcalfe P. A high resolution 2D array detector system for small-field MRI-linac applications. Biomed Phys Eng Express 2018. [DOI: 10.1088/2057-1976/aabd08] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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37
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Metcalfe P, De S, Bailly G. Augmented bladders and urinary diversions. Can Urol Assoc J 2018; 12:S24-S26. [PMID: 29681270 DOI: 10.5489/cuaj.5226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
| | - Shuba De
- University of Alberta, Edmonton, AB
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Brace O, Alhujaili S, Deshpande S, Vial P, Metcalfe P, Lerch M, Petasecca M, Rosenfeld A. EP-1773: Dual detector prototype for on line dose verification during patient radiotherapy treatment. Radiother Oncol 2018. [DOI: 10.1016/s0167-8140(18)32082-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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39
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Matar F, Wilkinson D, Davis J, Causer T, Fuduli I, Ceylan A, Carolan M, Metcalfe P, Petasecca M, Rosenfeld A. EP-1776: Verification of the NCS Code of Practice Report 24 for VMAT QA using a high-resolution detector. Radiother Oncol 2018. [DOI: 10.1016/s0167-8140(18)32085-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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40
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Choi JH, Cutajar D, Metcalfe P, Downes S. Application of MO
Skin
detector for
in vivo
dosimetry on total skin electron therapy (TSET). Biomed Phys Eng Express 2018. [DOI: 10.1088/2057-1976/aaac61] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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41
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Buckley JG, Wilkinson D, Malaroda A, Metcalfe P. Investigation of the radiation dose from cone-beam CT for image-guided radiotherapy: A comparison of methodologies. J Appl Clin Med Phys 2017; 19:174-183. [PMID: 29265684 PMCID: PMC5768018 DOI: 10.1002/acm2.12239] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 10/31/2017] [Accepted: 11/03/2017] [Indexed: 12/27/2022] Open
Abstract
Four methodologies were evaluated for quantifying kilovoltage cone‐beam computed tomography (CBCT) dose: the Cone‐Beam Dose Index (CBDI), IAEA Report 5 recommended methodology (IAEA), the AAPM Task Group 111 methodology (TG111), and the current dose metric; the Computed Tomography Dose Index (CTDI) on two commercial Varian cone‐beam CT imaging systems; the Clinac iX On‐Board Imager (OBI); and the TrueBeam X‐ray Imaging system (XI). The TG111 methodology measured the highest overall dose (21.199 ± 0.035 mGy OBI and 22.420 ± 0.002 XI for pelvis imaging) due to the full scatter of the TG111 phantom and was within 5% of CTDI measurements taken using a full scatter TG111 phantom and 30‐cm film strips. CBDI measured the second highest overall dose, within 10% of the TG111, with IAEA measuring the third highest dose. For head CBCT protocols, CBDI measured the highest dose, followed by IAEA. The CTDI method measured lowest across all scan modes highlighting its limitations for CBCT dosimetry. The XI imaging system delivered lower doses for head and thorax scan modes and similar doses to the OBI system for pelvis scan modes due to additional beam hardening filtration in the XI system. The TG111 method measured the highest dose in the center of a CBCT scan during image guidance procedures; however, CBDI provided a good approximation to TG111 with existing CTDI equipment and may be more applicable clinically.
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Affiliation(s)
- Jarryd G Buckley
- School of Physics, Centre for Medical and Radiation Physics, University of Wollongong, Wollongong, Australia
| | - Dean Wilkinson
- Illawarra Cancer Care Centre, Wollongong Hospital, Wollongong, Australia
| | - Alessandra Malaroda
- School of Physics, Centre for Medical and Radiation Physics, University of Wollongong, Wollongong, Australia
| | - Peter Metcalfe
- School of Physics, Centre for Medical and Radiation Physics, University of Wollongong, Wollongong, Australia
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42
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Alnaghy SJ, Begg J, Causer T, Alharthi T, Glaubes L, Dong B, George A, Holloway L, Metcalfe P. Technical Note: Penumbral width trimming in solid lung dose profiles for 0.9 and 1.5 T MRI-Linac prototypes. Med Phys 2017; 45:479-487. [DOI: 10.1002/mp.12680] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 09/19/2017] [Accepted: 11/07/2017] [Indexed: 11/10/2022] Open
Affiliation(s)
- Sarah J. Alnaghy
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2522 Australia
- Ingham Institute for Applied Medical Research; Liverpool NSW 2170 Australia
| | - Jarrad Begg
- Ingham Institute for Applied Medical Research; Liverpool NSW 2170 Australia
- Department of Medical Physics; Liverpool and Macarthur Cancer Therapy Centre; Liverpool NSW 2170 Australia
- South Western Sydney Clinical School; University of New South Wales, Liverpool; NSW 2170 Australia
| | - Trent Causer
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2522 Australia
- Ingham Institute for Applied Medical Research; Liverpool NSW 2170 Australia
- Illawarra Cancer Care Centre; Wollongong Hospital; Wollongong NSW 2500 Australia
| | - Thahabah Alharthi
- Ingham Institute for Applied Medical Research; Liverpool NSW 2170 Australia
- Institute of Medical Physics; University of Sydney; Camperdown NSW 2505 Australia
| | - Laura Glaubes
- Institute of Medical Physics; University of Sydney; Camperdown NSW 2505 Australia
| | - Bin Dong
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2522 Australia
- Ingham Institute for Applied Medical Research; Liverpool NSW 2170 Australia
- Department of Medical Physics; Liverpool and Macarthur Cancer Therapy Centre; Liverpool NSW 2170 Australia
| | - Armia George
- Ingham Institute for Applied Medical Research; Liverpool NSW 2170 Australia
- Department of Medical Physics; Liverpool and Macarthur Cancer Therapy Centre; Liverpool NSW 2170 Australia
| | - Lois Holloway
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2522 Australia
- Ingham Institute for Applied Medical Research; Liverpool NSW 2170 Australia
- Department of Medical Physics; Liverpool and Macarthur Cancer Therapy Centre; Liverpool NSW 2170 Australia
- South Western Sydney Clinical School; University of New South Wales, Liverpool; NSW 2170 Australia
- Institute of Medical Physics; University of Sydney; Camperdown NSW 2505 Australia. Sydney Medical School; University of Sydney; Camperdown NSW 2505 Australia
| | - Peter Metcalfe
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2522 Australia
- Ingham Institute for Applied Medical Research; Liverpool NSW 2170 Australia
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43
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Dundas K, Pogson EM, Batumalai V, Delaney GP, Boxer MM, Yap ML, Ahern V, Chan C, David S, Dimigen M, Harvey JA, Koh ES, Lim K, Papadatos G, Lazarus E, Descellar J, Metcalfe P, Holloway L. The impact of imaging modality (CT vs MRI) and patient position (supine vs prone) on tangential whole breast radiation therapy planning. Pract Radiat Oncol 2017; 8:e87-e97. [PMID: 28993138 DOI: 10.1016/j.prro.2017.07.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 07/11/2017] [Indexed: 12/25/2022]
Abstract
PURPOSE The purpose of this study was to evaluate the impact of magnetic resonance imaging (MRI) versus computed tomography (CT)-derived planning target volumes (PTVs), in both supine and prone positions, for whole breast (WB) radiation therapy. METHODS AND MATERIALS Four WB radiation therapy plans were generated for 28 patients in which PTVs were generated based on CT or MRI data alone in both supine and prone positions. A 6-MV tangential intensity modulated radiation therapy technique was used, with plans designated as ideal, acceptable, or noncompliant. Dose metrics for PTVs and organs at risk were compared to analyze any differences based on imaging modality (CT vs MRI) or patient position (supine vs prone). RESULTS With respect to imaging modality 2/11 whole breast planning target volume (WB_PTV) dose metrics (percentage of PTV receiving 90% and 110% of prescribed dose) displayed statistically significant differences; however, these differences did not alter the average plan compliance rank. With respect to patient positioning, the odds of having an ideal plan versus a noncompliant plan were higher for the supine position compared with the prone position (P = .026). The minimum distance between the seroma cavity planning target volume (SC_PTV) and the chest wall was increased with prone positioning (P < .001, supine and prone values 1.1 mm and 8.7 mm, respectively). Heart volume was greater in the supine position (P = .005). Heart doses were lower in the supine position than prone (P < .01, mean doses 3.4 ± 1.55 Gy vs 4.4 ± 1.13 Gy for supine vs prone, respectively). Mean lung doses met ideal dose constraints in both positions, but were best spared in the prone position. The contralateral breast maximum dose to 1cc (D1cc) showed significantly lower doses in the supine position (P < .001, 4.64 Gy vs 9.51 Gy). CONCLUSIONS Planning with PTVs generated from MRI data showed no clinically significant differences from planning with PTVs generated from CT with respect to PTV and doses to organs at risk. Prone positioning within this study reduced mean lung dose and whole heart volumes but increased mean heart and contralateral breast doses compared with supine.
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Affiliation(s)
- Kylie Dundas
- Centre for Medical Radiation Physics, Faculty of Engineering and Information Sciences, University of Wollongong, Wollongong, NSW, Australia; Liverpool and Macarthur Cancer Therapy Centres, Liverpool, NSW, Australia; Ingham Institute for Applied Medical Research, Liverpool Hospital, Sydney, NSW, Australia.
| | - Elise M Pogson
- Centre for Medical Radiation Physics, Faculty of Engineering and Information Sciences, University of Wollongong, Wollongong, NSW, Australia; Liverpool and Macarthur Cancer Therapy Centres, Liverpool, NSW, Australia; Ingham Institute for Applied Medical Research, Liverpool Hospital, Sydney, NSW, Australia; Institute of Medical Physics, School of Physics, University of Sydney, Sydney, NSW, Australia
| | - Vikneswary Batumalai
- Liverpool and Macarthur Cancer Therapy Centres, Liverpool, NSW, Australia; Ingham Institute for Applied Medical Research, Liverpool Hospital, Sydney, NSW, Australia; South Western Sydney Clinical School, University of New South Wales, Sydney, NSW, Australia
| | - Geoff P Delaney
- Liverpool and Macarthur Cancer Therapy Centres, Liverpool, NSW, Australia; Ingham Institute for Applied Medical Research, Liverpool Hospital, Sydney, NSW, Australia; South Western Sydney Clinical School, University of New South Wales, Sydney, NSW, Australia; School of Medicine, University of Western Sydney, Sydney, NSW, Australia
| | - Miriam M Boxer
- Liverpool and Macarthur Cancer Therapy Centres, Liverpool, NSW, Australia; South Western Sydney Clinical School, University of New South Wales, Sydney, NSW, Australia
| | - Mei Ling Yap
- Liverpool and Macarthur Cancer Therapy Centres, Liverpool, NSW, Australia; Ingham Institute for Applied Medical Research, Liverpool Hospital, Sydney, NSW, Australia; South Western Sydney Clinical School, University of New South Wales, Sydney, NSW, Australia; School of Medicine, University of Western Sydney, Sydney, NSW, Australia
| | - Verity Ahern
- Crown Princess Mary Cancer Care Centre, Westmead Hospital, NSW, Australia
| | - Christine Chan
- Department of Radiology, Liverpool Hospital, NSW, Australia
| | - Steven David
- Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
| | - Marion Dimigen
- Department of Radiology, Liverpool Hospital, NSW, Australia
| | - Jennifer A Harvey
- School of Medicine, University of Queensland, QLD, Australia; Princess Alexandra Hospital, QLD, Australia
| | - Eng-Siew Koh
- Liverpool and Macarthur Cancer Therapy Centres, Liverpool, NSW, Australia; Ingham Institute for Applied Medical Research, Liverpool Hospital, Sydney, NSW, Australia; South Western Sydney Clinical School, University of New South Wales, Sydney, NSW, Australia
| | - Karen Lim
- Liverpool and Macarthur Cancer Therapy Centres, Liverpool, NSW, Australia; South Western Sydney Clinical School, University of New South Wales, Sydney, NSW, Australia
| | - George Papadatos
- Liverpool and Macarthur Cancer Therapy Centres, Liverpool, NSW, Australia
| | | | - Joseph Descellar
- Ingham Institute for Applied Medical Research, Liverpool Hospital, Sydney, NSW, Australia; South Western Sydney Clinical School, University of New South Wales, Sydney, NSW, Australia
| | - Peter Metcalfe
- Centre for Medical Radiation Physics, Faculty of Engineering and Information Sciences, University of Wollongong, Wollongong, NSW, Australia; Liverpool and Macarthur Cancer Therapy Centres, Liverpool, NSW, Australia; Ingham Institute for Applied Medical Research, Liverpool Hospital, Sydney, NSW, Australia
| | - Lois Holloway
- Centre for Medical Radiation Physics, Faculty of Engineering and Information Sciences, University of Wollongong, Wollongong, NSW, Australia; Liverpool and Macarthur Cancer Therapy Centres, Liverpool, NSW, Australia; Ingham Institute for Applied Medical Research, Liverpool Hospital, Sydney, NSW, Australia; South Western Sydney Clinical School, University of New South Wales, Sydney, NSW, Australia
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44
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Alyami F, Fernandez N, Lee L, Metcalfe P, Lorenzo A, Pippi Salle J. Long-term follow-up after traditional versus modified perineal approach in the management of female epispadias. J Pediatr Urol 2017; 13:497.e1-497.e5. [PMID: 28392008 DOI: 10.1016/j.jpurol.2017.02.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 02/12/2017] [Indexed: 10/20/2022]
Abstract
OBJECTIVE Isolated female epispadias (IFE) is a rare congenital anomaly. The defect extends to the bladder neck, which is usually incompetent. The traditional surgical approach includes urethral and genital reconstruction in the first year, followed by bladder neck reconstruction (Young-Dees-Leadbetter cervicoplasty (YDL)) at the age of social continence. An alternative single-stage technique includes urethral, bladder neck and clitoris repair by a perineal approach. The aim of the present study was to describe long-term follow-up of patients who underwent the traditional vs alternative approach. MATERIALS AND METHODS A retrospective review was performed of all female epispadias cases managed between 2000 and 2013. The YDL procedure (Group 1) vs single-stage perineal approach (Group 2) cases were followed and compared. Collected variables included: patients' demographics, age at diagnosis and surgery, presence of associated anomalies, clinical presentation, presence of vesicoureteral reflux (VUR), and pre-operative and postoperative continence. RESULTS A total of 12 cases of female epispadias were managed and followed between 2000 and 2013. No major complications occurred in either group. Urinary continence evaluated in seven children showed that none (0/3) and 4/7 (57%) were continent following the initial procedure in Group 1 and Group 2, respectively. All patients in Group 1 failed to achieve continence and required re-intervention. CONCLUSIONS Female epispadias could be successfully repaired using a single-stage modified perineal approach that achieved good continence with volitional voiding, good cosmetic results and compared favorably with the ones repaired with the YDL technique. The additional step of performing bladder neck tailoring to achieve a funneling configuration seemed to be useful in improving continence.
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Affiliation(s)
- F Alyami
- Division of Urology, The Hospital for Sick Children and University of Toronto, Toronto, Ontario, Canada; Urology Division, Department of Surgery, King Saud University, King Saud University Medical City and College of Medicine, Riyadh, Saudi Arabia
| | - N Fernandez
- Division of Urology, The Hospital for Sick Children and University of Toronto, Toronto, Ontario, Canada
| | - L Lee
- Division of Urology, The Hospital for Sick Children and University of Toronto, Toronto, Ontario, Canada
| | - P Metcalfe
- Division of Pediatric Urology, Department of Pediatric Surgery, University of Alberta, Mackenzie Health Sciences Centre, Edmonton, Canada
| | - A Lorenzo
- Division of Urology, The Hospital for Sick Children and University of Toronto, Toronto, Ontario, Canada
| | - J Pippi Salle
- Division of Urology, The Hospital for Sick Children and University of Toronto, Toronto, Ontario, Canada; Department of Surgery, Division of Urology, Sidra Medical and Research Center, Doha, Qatar.
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45
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Roberts N, Oborn B, Begg J, George A, Alnaghy S, Causer T, Alharthi T, Jelen U, Dong B, Holloway L, Metcalfe P. Abstract ID: 47 Modelling of a novel X-ray source for MR-guided radiotherapy. Phys Med 2017. [DOI: 10.1016/j.ejmp.2017.09.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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46
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Vicoroski N, Espinoza A, Duncan M, Oborn BM, Carolan M, Metcalfe P, Menichelli D, Perevertaylo VL, Lerch MLF, Rosenfeld AB, Petasecca M. Development of a silicon diode detector for skin dosimetry in radiotherapy. Med Phys 2017; 44:5402-5412. [DOI: 10.1002/mp.12469] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 06/14/2017] [Accepted: 06/28/2017] [Indexed: 11/06/2022] Open
Affiliation(s)
- Nikolina Vicoroski
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2500 Australia
| | - Anthony Espinoza
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2500 Australia
| | - Mitchell Duncan
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2500 Australia
| | - Bradley M. Oborn
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2500 Australia
- Illawarra Cancer Care Centre; Wollongong Hospital; Wollongong NSW 2500 Australia
| | - Martin Carolan
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2500 Australia
- Illawarra Cancer Care Centre; Wollongong Hospital; Wollongong NSW 2500 Australia
| | - Peter Metcalfe
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2500 Australia
- Illawarra Health and Medical Research Institute - IHMRI; Wollongong NSW 2500 Australia
| | | | | | - Michael L. F. Lerch
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2500 Australia
- Illawarra Health and Medical Research Institute - IHMRI; Wollongong NSW 2500 Australia
| | - Anatoly B. Rosenfeld
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2500 Australia
- Illawarra Health and Medical Research Institute - IHMRI; Wollongong NSW 2500 Australia
| | - Marco Petasecca
- Centre for Medical Radiation Physics; University of Wollongong; Wollongong NSW 2500 Australia
- Illawarra Health and Medical Research Institute - IHMRI; Wollongong NSW 2500 Australia
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47
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Metcalfe P, Minchinton R, Murphy M, Waters A. Use of Chloroquine-Treated Granulocytes and Platelets in the
Diagnosis of Immune Cytopenias. Vox Sang 2017. [DOI: 10.1159/000466403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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48
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Doughty H, Murphy M, Metcalfe P, Rohatiner A, Lister T, Waters A. Relative Importance of Immune and Non-Immune Causes of Platelet Refractoriness. Vox Sang 2017. [DOI: 10.1159/000462509] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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49
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Murphy M, Pullon H, Metcalfe P, Chapman J, Jenkins E, Waters A, Nicolaides K, Mibashan R. Management of Fetal Alloimmune Thrombocytopenia by
Weekly in utero Platelet Transfusions. Vox Sang 2017. [DOI: 10.1159/000461076] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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50
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Deshpande S, Xing A, Metcalfe P, Holloway L, Vial P, Geurts M. Clinical implementation of an exit detector-based dose reconstruction tool for helical tomotherapy delivery quality assurance. Med Phys 2017; 44:5457-5466. [PMID: 28737014 DOI: 10.1002/mp.12484] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 07/04/2017] [Accepted: 07/11/2017] [Indexed: 11/08/2022] Open
Abstract
PURPOSE The aim of this study was to validate the accuracy of an exit detector-based dose reconstruction tool for helical tomotherapy (HT) delivery quality assurance (DQA). METHODS AND MATERIAL Exit detector-based DQA tool was developed for patient-specific HT treatment verification. The tool performs a dose reconstruction on the planning image using the sinogram measured by the HT exit detector with no objects in the beam (i.e., static couch), and compares the reconstructed dose to the planned dose. Vendor supplied (three "TomoPhant") plans with a cylindrical solid water ("cheese") phantom were used for validation. Each "TomoPhant" plan was modified with intentional multileaf collimator leaf open time (MLC LOT) errors to assess the sensitivity and robustness of this tool. Four scenarios were tested; leaf 32 was "stuck open," leaf 42 was "stuck open," random leaf LOT was closed first by mean values of 2% and then 4%. A static couch DQA procedure was then run five times (once with the unmodified sinogram and four times with modified sinograms) for each of the three "TomoPhant" treatment plans. First, the original optimized delivery plan was compared with the original machine agnostic delivery plan, then the original optimized plans with a known modification applied (intentional MLC LOT error) were compared to the corresponding error plan exit detector measurements. An absolute dose comparison between calculated and ion chamber (A1SL, Standard Imaging, Inc., WI, USA) measured dose was performed for the unmodified "TomoPhant" plans. A 3D gamma evaluation (2%/2 mm global) was performed by comparing the planned dose ("original planned dose" for unmodified plans and "adjusted planned dose" for each intentional error) to exit detector-reconstructed dose for all three "Tomophant" plans. Finally, DQA for 119 clinical (treatment length <25 cm) and three cranio-spinal irradiation (CSI) plans were measured with both the ArcCHECK phantom (Sun Nuclear Corp., Melbourne, FL, USA) and the exit detector DQA tool to assess the time required for DQA and similarity between two methods. RESULTS The measured ion chamber dose agreed to within 1.5% of the reconstructed dose computed by the exit detector DQA tool on a cheese phantom for all unmodified "Tomophant" plans. Excellent agreement in gamma pass rate (>95%) was observed between the planned and reconstructed dose for all "Tomophant" plans considered using the tool. The gamma pass rate from 119 clinical plan DQA measurements was 94.9% ± 1.5% and 91.9% ± 4.37% for the exit detector DQA tool and ArcCHECK phantom measurements (P = 0.81), respectively. For the clinical plans (treatment length <25 cm), the average time required to perform DQA was 24.7 ± 3.5 and 39.5 ± 4.5 min using the exit detector QA tool and ArcCHECK phantom, respectively, whereas the average time required for the 3 CSI treatments was 35 ± 3.5 and 90 ± 5.2 min, respectively. CONCLUSION The exit detector tool has been demonstrated to be faster for performing the DQA with equivalent sensitivity for detecting MLC LOT errors relative to a conventional phantom-based QA method. In addition, comprehensive MLC performance evaluation and features of reconstructed dose provide additional insight into understanding DQA failures and the clinical relevance of DQA results.
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Affiliation(s)
- Shrikant Deshpande
- Department of Medical Physics, Liverpool and Macarthur Cancer Therapy Centres and Ingham Institute, Sydney, NSW 2170, Australia.,Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Aitang Xing
- Department of Medical Physics, Liverpool and Macarthur Cancer Therapy Centres and Ingham Institute, Sydney, NSW 2170, Australia
| | - Peter Metcalfe
- Department of Medical Physics, Liverpool and Macarthur Cancer Therapy Centres and Ingham Institute, Sydney, NSW 2170, Australia.,Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Lois Holloway
- Department of Medical Physics, Liverpool and Macarthur Cancer Therapy Centres and Ingham Institute, Sydney, NSW 2170, Australia.,Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia.,Institute of Medical Physics, School of Physics, University of Sydney, Sydney, NSW 2006, Australia.,South West Sydney Clinical School, School of Medicine, University of NSW, Sydney, Australia
| | - Philip Vial
- Department of Medical Physics, Liverpool and Macarthur Cancer Therapy Centres and Ingham Institute, Sydney, NSW 2170, Australia.,Institute of Medical Physics, School of Physics, University of Sydney, Sydney, NSW 2006, Australia
| | - Mark Geurts
- Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
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